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Wed, 08 Jul 2026 07:34:00 -0700 (PDT) Received: from haichao.tail057a43.ts.net ([2001:da8:e000:1206:1b95:b995:f60c:5c67]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-847f6bcf03bsm7122862b3a.26.2026.07.08.07.33.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 08 Jul 2026 07:34:00 -0700 (PDT) From: Ruoyu Wang To: miquel.raynal@bootlin.com, richard@nod.at, vigneshr@ti.com Cc: mrugiero@gmail.com, computersforpeace@gmail.com, bbrezillon@kernel.org, linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org, Ruoyu Wang Subject: [PATCH] mtd: mtdswap: Avoid freeing registered blktrans device twice Date: Wed, 8 Jul 2026 22:33:55 +0800 Message-ID: <20260708143355.3166755-1-ruoyuw560@gmail.com> X-Mailer: git-send-email 2.51.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" In mtdswap_add_mtd(), debugfs setup failure after successful blktrans registration can free mbd_dev twice. add_mtd_blktrans_dev() initializes the blktrans device reference and publishes the disk. Once that succeeds, del_mtd_blktrans_dev() tears the disk down and drops the blktrans reference; when that reference reaches zero, blktrans_dev_release() frees the mtd_blktrans_dev. The debugfs failure path called del_mtd_blktrans_dev(mbd_dev), then fell through the common cleanup label and called kfree(mbd_dev) again. Clear the local pointer after deregistration so the common cleanup can still release the mtdswap state without freeing the blktrans object twice. This issue was found by a static analysis checker and confirmed by manual source review. Fixes: e8e3edb95ce6 ("mtd: create per-device and module-scope debugfs entri= es") Signed-off-by: Ruoyu Wang --- drivers/mtd/mtdswap.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/mtd/mtdswap.c b/drivers/mtd/mtdswap.c index 866933fc84265..533b8948918cb 100644 --- a/drivers/mtd/mtdswap.c +++ b/drivers/mtd/mtdswap.c @@ -1450,6 +1450,7 @@ static void mtdswap_add_mtd(struct mtd_blktrans_ops *= tr, struct mtd_info *mtd) =20 debugfs_failed: del_mtd_blktrans_dev(mbd_dev); + mbd_dev =3D NULL; =20 cleanup: mtdswap_cleanup(d); --=20 2.51.0